The invention relates generally to railcars, and more particularly to railcars for transportation of automotive vehicles.
For many years, autorack cars have been used for rail transport of automotive vehicles. A tri-level autorack car typically includes hinged end sections on the middle (xe2x80x9cBxe2x80x9d) deck to enable the each end of the deck to pivot between a lower position for supporting automotive vehicles and an upper position for increasing clearance to permit loading and unloading of vehicles on the bottom (xe2x80x9cAxe2x80x9d) deck.
The hinged end section is held in position by pins at opposite sides, and is manually lifted and lowered. To raise or lower the deck, a worker first releases a pin on one side, then releases a pin on the other side, then raises or lowers the deck to its new position. For many years, spring assist mechanisms have been employed to provide upward forces on the end sections to reduce the weight that must be handled by a worker raising or lowering the deck end. These mechanisms typically include a pair of coil springs loaded in tension, one on each side of the deck. The spring mechanisms provide sufficient lift that when the deck end is in its lower position, it is biased upward. However, in its upper position, the lift is decreased, and the deck end will tend to drop toward a middle, neutral position when released from its upper position. Similarly, the spring force above is sufficient to lift the deck to a neutral position when it is released from its lower position. When a pin is unlocked on one side of the deck, that side moves a sufficient distance toward a neutral position to enable the pin to be released without the pin returning to the locked position.
Within the last few years, trilevel railcars have been developed that have bottom (xe2x80x9cAxe2x80x9d) decks more deeply recessed than those of the earlier trilevel cars discussed above. As a result, longer, heavier hinged end sections having greater vertical travel have been provided on their xe2x80x9cBxe2x80x9d decks to provide clearance.
While the prior art spring assist mechanisms described above have been commercially successful and have proven satisfactory in operation, it would be difficult or impossible for a worker to handle the longer, heavier hinged end sections without more lift than that provided by the prior art spring assist mechanisms.
In providing a satisfactory mechanism to assist in raising and lowering the larger hinged deck portions, a number of considerations must be addressed. Due to the requirements for ventilation of railcars carrying automotive vehicles, the railcar interior is, to some extent, exposed to temperature extremes and other harsh weather conditions and to ingress of airborne particulate matter. The mechanism must be capable of operating satisfactorily while withstanding such exposure for periods of several years of commercial use. In addition, the mechanism must be capable of withstanding continuously varying dynamic loads associated with the travel of the railcar while the railcar is in motion. Furthermore, the mechanism should be relatively simple to operate due to the fact that, over the course of its service life, the mechanism is likely to be operated by many different workers having varying degrees of skill and training. On a related point, the mechanism should be capable of withstanding misuse without jamming or otherwise failing. Also, the mechanism must not unduly increase the cost or weight of the railcar, and must not unduly restrict interior clearances.
One possible alternative to the prior art mechanisms is to employ one or more hand-cranked winch mechanisms. See, e.g., U.S. Pat. No. 5,743,192 to Saxton et al. However, it is believed that the time required for hand cranking of such winch mechanisms is a significant disadvantage.
Another possible alternative is to rely upon hand-held power tools to interface with winch mechanisms. However, this approach would have significant disadvantages in requiring specialized power tools and power sources for the tools to be available on the railcar or at loading and unloading locations, with the consequence of unavailability or mechanical failure of the tools or power sources at a particular site being potentially costly delays in loading and unloading operations. To avoid this problem, it is desirable that a mechanism for assisting in raising and lowering hinged deck end sections be operable without requiring any equipment other than that provided on the railcar, and without requiring an external power source.
It is a general object of the invention to provide an improved system to assist a single worker to efficiently and safely raise or lower a hinged deck portion of a trilevel railcar.
The invention provides a novel mechanism to assist in raising and lowering a large, heavy hinged deck end section such that a single worker can raise or lower the deck end section quickly and efficiently. Lifting force is applied to the deck end section by a counterweight mechanism. In the preferred embodiment, the counterweight mechanism operates in conjunction with a conventional, proven spring assist mechanism of the type that has been used in the past on trilevel railway cars. The counterweight mechanism preferably includes a counterweight that is slidable along a vertical track in a location that is readily accessible for visual inspection and maintenance. Nonmetallic wear pads are preferably employed in conjunction with a dry film lubricant to control friction between the counterweight and the track. The mechanism preferably provides a mechanical advantage so that the lifting force applied by the counterweight mechanism exceeds the weight of the counterweight. A roller chain, steel cable, or the like is preferably employed to connect the weight to the deck end section.